https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64644
Bug ID: 64644
Summary: "warning: anonymous union with no members" should be
an error with -pedantic-errors
Product: gcc
Version: 4.9.2
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: harald at gigawatt dot nl
Compiling
static union { };
with gcc -std=c++11 -pedantic-errors gives
test.cc:1:16: warning: anonymous union with no members
static union { };
^
It's fine that it's a warning by default, but I think it should be an error
with -pedantic-errors, because it violates the last part of [dcl.dcl]p3: when
the init-declarator-list is omitted, "the decl-specifier-seq shall introduce
one or more names into the program, or shall redeclare a name introduced by a
previous declaration." No exception is made for anonymous unions, so the only
way an anonymous union can avoid violating this is by having members.
(FWIW, I cannot find any options to get any warning whatsoever with clang,
Intel or Sun, and MSVC only warns at the highest warning level, regardless of
whether language extensions are enabled. As far as I can tell, GCC's current
handling is already the best of these five.)
